A bearing seal device for use in industrial dust-laden wet flue gas and a method of manufacturing the same

Abstract

The application discloses a bearing sealing device used in industrial dust-containing wet flue gas and a preparation method thereof. The device comprises upper and lower sealing sleeve assemblies, and a static sealing ring and a rotating sealing ring matched with each other are arranged in the assemblies. The static sealing ring is connected with a device shell, and the rotating sealing ring is in interference fit with a rotating shaft. Each sealing ring is made of modified polyformal material, and the material comprises copolyformal, polytetrafluoroethylene powder, glass fiber and an antioxidant. The device has the advantages of corrosion resistance, good wear resistance, size stability and effective adaptation to severe working conditions, and the preparation method has the advantages of simple process and low cost.

Description

Technical Field

[0001] This invention relates to the field of sealing technology, specifically to a bearing sealing device used in industrial dusty wet flue gas and its preparation method. Background Technology

[0002] Currently, mainstream labyrinth seal products are mainly divided into two categories: one is made of metal, which relies on precision machining and has certain strength, but has obvious defects, such as being heavy, costly, and susceptible to corrosion; the other is made of ordinary plastic, which achieves lightweighting, but has poor wear resistance, with a friction coefficient ≥0.4 at high speeds, making it prone to wear. At the same time, it is prone to creep at high temperatures, resulting in a dimensional change rate of ≥1% in the sealing gap within one year, causing the sealing effect to fail rapidly. At low temperatures, it is prone to embrittlement, further limiting its application range.

[0003] Existing technologies for improving labyrinth seals mainly focus on structural optimization or material replacement, but none of them solve the core problems. For example, using a multi-level groove structure to improve the sealing effect does not solve the problems of weight and corrosion of metal materials, and it is still unable to adapt to working conditions with high humidity and corrosive gases; or adding glass fiber reinforcement, but the coefficient of friction is still ≥0.35, and it is prone to embrittlement at low temperatures, which cannot meet the requirements of wide temperature range working conditions. In addition, existing technologies have not applied polyoxymethylene to the field of labyrinth seals, and have not disclosed the synergistic design of material modification and structural optimization, resulting in the inability to simultaneously solve multiple problems such as large weight, high cost, poor wear resistance, and insufficient temperature resistance, and failing to meet the long-term stable operation requirements of rotating equipment in industrial dusty and wet flue gas. Summary of the Invention

[0004] The purpose of this invention is to provide a bearing sealing device and its preparation method for use in industrial dusty wet flue gas, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following solution: A bearing sealing device for use in industrial dusty wet flue gas includes an upper sealing sleeve assembly and a lower sealing sleeve assembly; The upper sealing sleeve assembly includes a coaxial clearance-fitted upper sealing sleeve stationary sealing ring and an upper sealing sleeve rotating sealing ring. The lower sealing sleeve assembly includes a coaxial clearance-fitted lower sealing sleeve stationary sealing ring and a lower sealing sleeve rotating sealing ring. Both the upper sealing sleeve static sealing ring and the lower sealing sleeve static sealing ring are used to connect with the equipment housing; Both the upper sealing sleeve rotary sealing ring and the lower sealing sleeve rotary sealing ring are used to be sleeved on the bearing shaft and have an interference fit with the bearing shaft. The upper sealing sleeve stationary sealing ring and the upper sealing sleeve rotating sealing ring interlock to form a multi-level zigzag maze channel; The lower sealing sleeve stationary sealing ring and the lower sealing sleeve rotating sealing ring interlock to form a multi-level zigzag maze channel; The upper sealing sleeve stationary sealing ring, the upper sealing sleeve rotating sealing ring, the lower sealing sleeve stationary sealing ring, and the lower sealing sleeve rotating sealing ring are all made of modified polyoxymethylene material. The modified polyoxymethylene material is composed of a copolymerized polyoxymethylene matrix and polytetrafluoroethylene micro powder, glass fiber, and antioxidant added to the copolymerized polyoxymethylene matrix.

[0006] Furthermore, by weight percentage, the modified polyoxymethylene material comprises the following components: 5%-10% polytetrafluoroethylene micro powder; 2%-5% glass fiber; Antioxidant 0.1%-0.3%; The remainder is copolymerized formaldehyde.

[0007] Furthermore, the radial gap of the multi-level zigzag maze channel is 0.1-0.3 mm, and the axial overlap length is 14.5-16 mm.

[0008] Furthermore, the inner diameters of the upper sealing sleeve rotating sealing ring and the lower sealing sleeve rotating sealing ring are 0.1-0.15 mm smaller than the corresponding bearing shaft diameter.

[0009] Furthermore, both the upper sealing sleeve stationary sealing ring and the lower sealing sleeve stationary sealing ring are provided with annular bosses, and the top of the annular bosses is provided with rounded corners with a radius of 0.2-0.3mm.

[0010] Furthermore, both the upper sealing sleeve stationary sealing ring and the lower sealing sleeve stationary sealing ring are provided with radially extending dustproof eaves at the entrance of the multi-level zigzag labyrinth channel, and the axial gap between the dustproof eaves and the upper sealing sleeve rotating sealing ring or the lower sealing sleeve rotating sealing ring is 0.3-0.5mm.

[0011] The present invention also provides a method for preparing the above-mentioned bearing sealing device for use in industrial dusty wet flue gas, comprising the following steps: Step S1: Weigh out the co-oxygenation, polytetrafluoroethylene micro powder, glass fiber and antioxidant according to the formula ratio, and mix the components evenly. Step S2: The mixed materials are melt-extruded and granulated to obtain modified polyoxymethylene granules; Step S3: Dry the modified polyoxymethylene particles; Step S4: The dried modified polyoxymethylene granules are molded to obtain the upper sealing sleeve stationary sealing ring, the upper sealing sleeve rotating sealing ring, the lower sealing sleeve stationary sealing ring and the lower sealing sleeve rotating sealing ring respectively. Step S5: Perform post-processing on each formed sealing ring to eliminate internal stress; Step S6: Press the upper sealing sleeve rotating sealing ring and the lower sealing sleeve rotating sealing ring onto the corresponding positions of the bearing shaft; install the upper sealing sleeve stationary sealing ring and the lower sealing sleeve stationary sealing ring onto the equipment housing; assemble them into the upper sealing sleeve assembly and the lower sealing sleeve assembly respectively.

[0012] Furthermore, in step S4, the molding process is injection molding; In step S5, the post-processing is annealing.

[0013] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows: Compared to traditional metal seals, this invention uses modified polyoxymethylene material, which significantly reduces the weight of the device and decreases the inertia of the equipment during operation. At the same time, this material has extremely high chemical stability in the acid and alkali corrosive environment of industrial dusty wet flue gas, which completely solves the problem of easy corrosion and failure of metal parts and significantly extends the service life.

[0014] Compared to ordinary plastic seals, this invention, through synergistic design and material modification, effectively reduces the coefficient of friction and improves wear resistance by adding polytetrafluoroethylene (PTFE) micropowder; the addition of glass fiber significantly enhances material rigidity and suppresses creep at high temperatures. Tests show that this device exhibits extremely low dimensional change rate during long-term operation under high temperature, acid and alkali corrosion, and high dust conditions, avoiding seal failure due to deformation, and also has a wider temperature resistance range and is less prone to embrittlement at low temperatures.

[0015] The system employs a multi-stage, labyrinthine passageway with precise radial clearance and axial overlap, forming a highly efficient throttling and pressure-reducing barrier. Combined with the inlet dustproof eaves, it effectively prevents the intrusion of large dust particles. Furthermore, the annular boss and rounded corner design facilitate assembly guidance and dampen vibrations, further enhancing the reliability of the device's operation.

[0016] The process employs injection molding and post-annealing treatment, resulting in high production efficiency and good product consistency. Compared with precision metal machining, it significantly reduces manufacturing costs and is easy to promote industrially. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the combined structure of the upper sealing sleeve assembly in this invention; Figure 2 This is a schematic diagram of the static sealing ring of the upper sealing sleeve in this invention; Figure 3 This is a schematic diagram of the structure of the rotating sealing ring of the upper sealing sleeve in this invention; Figure 4 This is a schematic diagram of the combined structure of the lower sealing sleeve assembly in this invention; Figure 5 This is a schematic diagram of the structure of the stationary sealing ring of the lower sealing sleeve in this invention; Figure 6 This is a schematic diagram of the structure of the rotating sealing ring of the lower sealing sleeve in this invention.

[0019] Explanation of reference numerals in the attached figures: 1. Upper sealing sleeve stationary sealing ring; 2. Upper sealing sleeve rotating sealing ring; 3. Lower sealing sleeve stationary sealing ring; 4. Lower sealing sleeve rotating sealing ring. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0022] Example 1

[0023] like Figures 1 to 6As shown, this embodiment provides a bearing sealing device for use in industrial dusty wet flue gas. This device is applied inside the cylinder of a dust removal equipment to seal the bearings at both ends of the fan blades within the cylinder, preventing dusty wet flue gas from entering the bearing cavity and damaging the bearings. The device includes an upper sealing sleeve assembly and a lower sealing sleeve assembly.

[0024] The upper sealing sleeve assembly is located at the upper end of the rotating shaft and mainly consists of the upper sealing sleeve stationary sealing ring 1 and the upper sealing sleeve rotating sealing ring 2.

[0025] The lower sealing sleeve assembly is located at the lower end of the rotating shaft and mainly consists of the lower sealing sleeve stationary sealing ring 3 and the lower sealing sleeve rotating sealing ring 4.

[0026] Specifically, regarding the structure of the upper sealing sleeve stationary sealing ring 1: like Figure 2 As shown, the upper sealing sleeve stationary sealing ring 1 has a cylindrical structure, and its outer peripheral wall is used for fixed connection with the cylindrical shell of the dust removal equipment. Several sealing teeth protruding towards the center are provided on its inner peripheral wall along the circumferential direction. To improve the sealing effect and guide the fluid, a dustproof eave is provided at the entrance of the labyrinth passage of the upper sealing sleeve stationary sealing ring 1. This dustproof eave extends radially inward to prevent large dust particles from directly entering the depths of the labyrinth.

[0027] Specifically, the axial clearance between the dustproof eaves and the rotary sealing ring is 0.3-0.5mm.

[0028] In addition, an annular boss is provided at the end of the stationary sealing ring 1 of the upper sealing sleeve. The top of the annular boss is chamfered to form a rounded corner with a radius of 0.2-0.3 mm. This rounded corner design helps guide the mating parts during assembly and reduces stress concentration. The stationary sealing ring 1 of the upper sealing sleeve and the rotating sealing ring 2 of the upper sealing sleeve are coaxially arranged, with a gap between them.

[0029] Specifically, regarding the structure of the upper sealing sleeve rotating sealing ring 2: like Figure 3 As shown, the upper sealing sleeve rotary sealing ring 2 is also cylindrical and is fitted onto the bearing shaft. To ensure coaxial rotation and prevent slippage, the inner diameter of the upper sealing sleeve rotary sealing ring 2 is designed to be 0.1-0.15 mm smaller than the corresponding bearing shaft diameter, and it is fastened to the shaft by an interference fit. The outer peripheral wall of the upper sealing sleeve rotary sealing ring 2 is provided with sealing teeth that interlock with the sealing teeth on the inner wall of the upper sealing sleeve stationary sealing ring 1.

[0030] Regarding the structure of the level 4 square-shaped maze: Please refer to this carefully. Figure 1, when the upper static seal ring 1 and the upper rotating seal ring 2 of the upper seal sleeve are assembled by being buckled together, the teeth and grooves between the two are interlocked in a staggered manner, forming a zigzag sealing path. This path presents a zigzag structure in the axial section, specifically defined as a 4-level zigzag labyrinth channel. These 4 levels of labyrinth mean that when air flow or dust particles pass through this gap, they need to undergo 4 direction mutations (including radial and axial turns), thus greatly increasing the fluid resistance and achieving effective sealing. According to the preferred parameters of this embodiment, the radial gap of this 4-level zigzag labyrinth channel is controlled between 0.1 - 0.3 mm, and the axial overlapping length (i.e., the overlapping length of teeth in the axial direction) is 14.5 - 16 mm. This tight and multi-level matching structure can effectively block the intrusion of industrial dusty wet flue gas.

[0031] It should be noted that the number of labyrinth levels can be adjusted according to the protection level requirements, and it is not limited to a 4-level labyrinth.

[0032] Specifically, regarding the structure of the lower seal sleeve assembly: As Figures 4 to 6 shown, the structure of the lower seal sleeve assembly is basically symmetrical to that of the upper seal sleeve assembly.

[0033] The lower static seal ring 3 of the lower seal sleeve (as Figure 5 shown) is fixed to the equipment housing, its inner wall is provided with sealing teeth, a dust-proof eaves is also provided at the entrance, and an annular boss with a rounded corner is provided at the end.

[0034] The lower rotating seal ring 4 of the lower seal sleeve (as Figure 6 shown) is installed on the lower end of the rotating shaft by interference fit, and its outer wall is provided with sealing teeth that cooperate with the lower static seal ring 3 of the lower seal sleeve.

[0035] After the lower static seal ring 3 and the lower rotating seal ring 4 of the lower seal sleeve are assembled, a 4-level zigzag labyrinth channel is also formed, and its structural parameters are the same as those of the upper assembly, ensuring the same sealing protection for the upper and lower bearings.

[0036] In this embodiment, the four key components, namely the upper static seal ring 1, the upper rotating seal ring 2, the lower static seal ring 3, and the lower rotating seal ring 4 of the lower seal sleeve, are integrally injection-molded using a modified polyoxymethylene material.

[0037] Embodiment 2

[0038] This embodiment details the components and preparation method of the modified polyoxymethylene material in Embodiment 1.

[0039] The modified polyoxymethylene material consists of a copolymerized polyoxymethylene matrix and additives added to the copolymerized polyoxymethylene matrix. By weight percentage, the components are as follows: Polytetrafluoroethylene (PTFE) micropowder: 5% - 10%; Fiberglass: 2%-5%; Antioxidant: 0.1%-0.3%; The balance is polyoxymethylene (POM).

[0040] This formulation reduces the wear rate of the sealing ring during high-speed rotation by adding PTFE micropowder to the POM matrix, utilizing PTFE's low coefficient of friction. The addition of glass fiber significantly improves the material's rigidity and dimensional stability, preventing creep in high-temperature and humid flue gas environments. Antioxidants also slow down the material's aging process.

[0041] Specifically, polytetrafluoroethylene (PTFE) is used to reduce the coefficient of friction and improve self-lubrication; glass fiber is used to enhance creep resistance and reduce the rate of dimensional change at high temperatures; and the antioxidant is 1010 antioxidant, which is used to delay material aging.

[0042] The modified material has a Shore hardness of 85-90D, an elongation at break of ≥40%, a coefficient of friction of ≤0.2, and a dimensional change rate of ≤0.3% from -40℃ to 120℃.

[0043] The method for preparing a bearing sealing device includes the following steps: Step S1: Weigh out the co-oxygenation, polytetrafluoroethylene micro powder, glass fiber and antioxidant according to the formula ratio, and mix the components evenly. Step S2: The mixed materials are melt-extruded and granulated to obtain modified polyoxymethylene granules; Step S3: Dry the modified polyoxymethylene particles; Step S4: The dried modified polyoxymethylene granules are molded to obtain an upper sealing sleeve stationary sealing ring, an upper sealing sleeve rotating sealing ring, a lower sealing sleeve stationary sealing ring, and a lower sealing sleeve rotating sealing ring. Step S5: Perform post-processing on each formed sealing ring to eliminate internal stress; Step S6: Press the upper sealing sleeve rotating sealing ring and the lower sealing sleeve rotating sealing ring onto the corresponding positions of the bearing shaft; install the upper sealing sleeve stationary sealing ring and the lower sealing sleeve stationary sealing ring onto the equipment housing; assemble them into the upper sealing sleeve assembly and the lower sealing sleeve assembly respectively.

[0044] It should be noted that in step S4, the molding process is injection molding; in step S5, the post-processing is annealing.

[0045] It should be noted that the mold preparation accuracy is ±0.02mm to ensure the tolerance of the labyrinth gap.

[0046] Injection parameters: Barrel temperature 170-190℃, mold temperature 60-80℃, injection pressure 80-100MPa.

[0047] Post-treatment: Anneal at 120℃ for 2 hours to relieve internal stress.

[0048] Performance advantages: Wear resistance: 50% higher than metal seals, 200% higher than nylon seals (life ≥ 3 years at 3000r / min); Sealing efficiency: ≥99% blocking rate against water and dust particles larger than 1μm, which is superior to the 95% of existing metal seals; Environmental adaptability: It does not become brittle at -40℃ and does not creep at 120℃, making it suitable for harsh working conditions.

[0049] Economic advantages: Weight: The weight of a single seal is ≤100g (approximately 200g for metal seals), reducing equipment inertial energy consumption; Cost: Injection molding processing costs are 40%-60% lower than metal machining, and material costs are comparable to nylon.

[0050] Technological advantages: It can be mass-produced (mold life ≥ 100,000 times) and is suitable for large-scale applications; No post-processing is required, reducing production steps.

[0051] Example 3

[0052] This embodiment describes a bearing sealing device used in medium-high temperature, dusty, watery, and acidic operating conditions (sealing of dust removal equipment in desulfurization towers of steel plants). Structural parameters: 4-level labyrinth, radial clearance 0.15mm, axial overlap length 14.5mm; boss height 16mm.

[0053] Material formula: Copolymerized formaldehyde + 6% PTFE micro powder + 5% glass fiber + 0.3% antioxidant 1010.

[0054] Performance testing: After 12 months of operation at 80℃, pH 3.0, 2500r / min, and a dust concentration of 100mg / m³, the dimensional change rate was 0.25%, with no deformation or leakage.

[0055] Example 4

[0056] This embodiment describes a bearing sealing device used in medium-high temperature, dusty, watery, and alkaline operating conditions (sealing of dust removal equipment in power plant desulfurization towers). Structural parameters: 4-level labyrinth, radial clearance 0.15mm, axial overlap length 14.5mm; boss height 16mm.

[0057] Material formula: Copolymerized formaldehyde + 10% PTFE micro powder + 3% glass fiber + 0.3% antioxidant 1010.

[0058] Performance testing: After 12 months of operation at 80℃, pH 10.0, 2500r / min, and a dust concentration of 50mg / m³, the dimensional change rate was 0.25%, with no deformation or leakage.

[0059] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A bearing sealing device used in industrial dusty wet flue gas, characterized in that, Includes an upper sealing sleeve assembly and a lower sealing sleeve assembly; The upper sealing sleeve assembly includes a coaxial clearance-fitted upper sealing sleeve stationary sealing ring and an upper sealing sleeve rotating sealing ring. The lower sealing sleeve assembly includes a coaxial clearance-fitted lower sealing sleeve stationary sealing ring and a lower sealing sleeve rotating sealing ring. Both the upper sealing sleeve static sealing ring and the lower sealing sleeve static sealing ring are used to connect with the equipment housing; Both the upper sealing sleeve rotary sealing ring and the lower sealing sleeve rotary sealing ring are used to be sleeved on the bearing shaft and have an interference fit with the bearing shaft. The upper sealing sleeve stationary sealing ring and the upper sealing sleeve rotating sealing ring interlock to form a multi-level zigzag maze channel; The lower sealing sleeve stationary sealing ring and the lower sealing sleeve rotating sealing ring interlock to form a multi-level zigzag maze channel; The upper sealing sleeve stationary sealing ring, the upper sealing sleeve rotating sealing ring, the lower sealing sleeve stationary sealing ring, and the lower sealing sleeve rotating sealing ring are all made of modified polyoxymethylene material. The modified polyoxymethylene material is composed of a copolymerized polyoxymethylene matrix and polytetrafluoroethylene micro powder, glass fiber, and antioxidant added to the copolymerized polyoxymethylene matrix.

2. The bearing sealing device for use in industrial dusty wet flue gas according to claim 1, characterized in that, The modified polyoxymethylene material comprises the following components by weight percentage: 5%-10% polytetrafluoroethylene micro powder; 2%-5% glass fiber; Antioxidant 0.1%-0.3%; The remainder is copolymerized formaldehyde.

3. The bearing sealing device for use in industrial dusty wet flue gas according to claim 1, characterized in that, The radial gap of the multi-level zigzag maze channel is 0.1-0.3 mm, and the axial overlap length is 14.5-16 mm.

4. The bearing sealing device for use in industrial dusty wet flue gas according to claim 1, characterized in that, The inner diameters of the upper sealing sleeve rotating sealing ring and the lower sealing sleeve rotating sealing ring are 0.1-0.15 mm smaller than the corresponding bearing shaft diameter.

5. The bearing sealing device for use in industrial dusty wet flue gas according to claim 1, characterized in that, Both the upper sealing sleeve stationary sealing ring and the lower sealing sleeve stationary sealing ring are provided with annular bosses, and the top of the annular bosses is provided with rounded corners with a radius of 0.2-0.3mm.

6. The bearing sealing device for use in industrial dusty wet flue gas according to claim 1, characterized in that, Both the upper sealing sleeve stationary sealing ring and the lower sealing sleeve stationary sealing ring are provided with radially extending dustproof eaves at the entrance of the multi-level U-shaped labyrinth channel. The axial gap between the dustproof eaves and the upper sealing sleeve rotating sealing ring or the lower sealing sleeve rotating sealing ring is 0.3-0.5mm.

7. A method for preparing a bearing sealing device for use in industrial dusty wet flue gas as described in any one of claims 1-6, characterized in that, Includes the following steps: Step S1: Weigh out the co-oxygenation, polytetrafluoroethylene micro powder, glass fiber and antioxidant according to the formula ratio, and mix the components evenly. Step S2: The mixed materials are melt-extruded and granulated to obtain modified polyoxymethylene granules; Step S3: Dry the modified polyoxymethylene particles. Step S4: The dried modified polyoxymethylene granules are molded to obtain the upper sealing sleeve stationary sealing ring, the upper sealing sleeve rotating sealing ring, the lower sealing sleeve stationary sealing ring and the lower sealing sleeve rotating sealing ring respectively. Step S5: Perform post-processing on each formed sealing ring to eliminate internal stress; Step S6: Press the upper sealing sleeve rotating sealing ring and the lower sealing sleeve rotating sealing ring onto the corresponding positions of the bearing shaft; The upper sealing sleeve stationary sealing ring and the lower sealing sleeve stationary sealing ring are respectively installed on the equipment housing; and respectively assembled into the upper sealing sleeve assembly and the lower sealing sleeve assembly.

8. The method for preparing a bearing sealing device for use in industrial dusty wet flue gas according to claim 6, characterized in that, In step S4, the molding process is injection molding; In step S5, the post-processing is annealing.

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